Characterization of the biodegradability of complex wastes

Chemosphere, Vol.17, No.lO, pp 2073-2082, Printed in Great Britain

1988

0 0 4 5 - 6 5 3 5 / 8 8 $3.00 + .00 P e r g a m o n Press plc

C h a r a c t e r i z a t i o n of t h e B i o d e g r a d a b i l i t y of C o m p l e x W a s t e s

P. L i n d g a a r d - J ~ r g e n s e n a n d N i e l s N y h o l m * Water Quality Institute, ATV DK ~ 2970

H~rsholm

Denmark Abstract:

A

method

such

to

as

characterize

industrial

the

biodegradability

effluents

is

presented

of

and

complex

wastes

illustrated

by

a

c a s e study. The c o u r s e of b i o d e g r a d a t i o n is f o l l o w e d by non-compound specific tested

analyses

for

and the

toxic

effects

non-degradable and

screened

(persistent)

fraction

for p o t e n t i a l l y

is

bioaccumu-

l a t i n g compounds.

Introduction: For test

assessing

procedures

parameters demand fic

biodegradability are

available

which

prescribe

like d i s s o l v e d o r g a n i c c a r b o n

analyses

to

follow

Examples

the

course

of m e t h o d s

the C l o s e d B o t t l e t e s t

(I).

If,

of the

for

instance,

28 days

with

individual

(BOD) or c h e m i c a l o x y g e n d e m a n d

compound.

cluded

of

70%

compounds, the use

the

a mixture

degraded

contains

Methods

for

DOC

initially

of c h e m i c a l

products

the

components,

active

detergents. present address:

is

also

of

or n o n - r e a d i l y

for

however,

County of $torstr~m,

within

it is con-

that the unbiodegradable

biodegradability

b e e n b a s e d on a n a l y s e s

instance

anionic

surfactants

is not g e n e r a l l y a p p l i c a b l e to

Environmental

Office,

Perkvej 37, DK-4~O Nyk~ing F., Demlark

2073

of the

test

(I) and

(2) . However,

it is quite c o n c e i v a b l e

have traditionally

T h i s method,

the

added degrades

degradable

determination

like

oxygen

(COD) a n d / o r c o m p o u n d - s p e c i -

of b i o d e g r a d a t i o n

persistent

the

summary

are the O E C D s c r e e n i n g t e s t

3D%

of chemicals,

residue

compounds.

remaining

of

(DOC), b i o c h e m i c a l

in t h e s e tests p e r f o r m e d w i t h single compounds, that

standard

of in

2074

mixtures

in which the identity

which chemical Combining

analyses

snmmary

fingerprints

of the compounds

are not available

parameters

with

is unknown

bioassays

(2)

and

analytical

(2) has proved to produce better information

ging the degradability

or for

(2).

of chemical mixtures,

for jud-

e.g. industrial wastes

(3,4). In the

method

wastewater (DOC

and

combined

group with

accumulating of

the

here,

variables

compounds. OECD

natural

like and

biodegradability

adsorbable

organic for

The test

systems test

water

and

used an

with high concentrations

industrial analyses

halides

(AOX))

potentially

were

(i) performed (2)

of

specific

TLC-screenings

screening

surface

(2) performed

the

is studied using non-compound

bioassays

modified

enriched test

presented

samples

aerobic

a

bio-

(i) variant

with

nutrient

stabilization

of test material.

TOC Freshly colleco-I"~' acute toxicit~ i~ed waste ~ chemical characterization obtional)

/

~ Residje" ~ A

Fig. i: Fig.

Principles

acute end chronic toxidty TLC screening of bioaccumulative subsfanceschemical characferiza~ion (in case of concearn)

of the biodegradability

of the organic wastes.

1 shows the time course of biodegradation

bilization

test.

As

shown,

the method

in the aerobic

combines

the three major parameters

which make a chemical

mentally

persistency,

toxicity.

harmful,

namely:

investigations compound

accumulation

staof

environ-

tendency

and

2075

MATERIALS

AND

METHODS

Sampling F o r the case study, 24 h o u r t i m e p r o p o r t i o n a l s a m p l e s of w a s t e water from

different

Sweden

were

petrochemical

sampled

in

industries

polyethylene

located

bottles

at

and

Stenungssund,

frozen

(-20°C),

(i0,ii).

T h e t e s t m e d i u m was a s a m p l e of s e a w a t e r from the K a t t e g a t c o l l e c t e d i0

cm

had

below

been

the

surface

thoroughly

in

rinsed

25

litre

polyethylene

in 0.2 N HCL.

The

bottles,

samples

were

which stored

at t h e f i e l d t e m p e r a t u r e and u s e d w i t h i n 24 hours. BIODEGRADABILITY

STUDIES

T h e s c r e e n i n g of the b i o d e g r a d a b i l i t y of the e f f l u e n t s was performed as s h a k e water

flask die-away tests

enriched with

(5) at 4°C and 15°C in n a t u r a l

nutrients.

The c o n c e n t r a t i o n

sea-

of t e s t m a t e r i a l

w a s 15-25 m g / l DOC (i). T h e flasks w e r e i n c u b a t e d on a r o t a r y s h a k e r in a t e m p e r a t u r e - c o n t r o l l e d

r o o m u n d e r d i f f u s e light.

The aerobic stabilization test 15°C w i t h DOC 25

mixtures

concentrations litre

glass

43) was p e r f o r m e d d u r i n g 60 days at

of w a s t e w a t e r were

bottles,

and s e a w a t e r

200-300 mg/l. stirred

and

(1:3 v o l / v o l ) .

The

The tests w e r e p e r f o r m e d aerated

with

GAC

in

(granular

a c t i v a t e d carbon) r i n s e d air, in o r d e r to m a i n t a i n an o x y g e n tension h i g h e r t h a n 70% of s a t u r a t i o n .

E v a p o r a t i o n was m i n i m i z e d by p a s s i n g

the e x i t gas t h r o u g h a r e f l u x 'condensor. The e x t e n t of b i o d e g r a d a t i o n was d e t e r m i n e d by DOC and A O X analyses.

The

screening

formed in

a

using

short

tests

and the a e r o b i c

a non-toxic

term

stabilization

concentration

respiration

to the D a n i s h s t a n d a r d DS 298

test (5).

with

tests w e r e

per-

of w a s t e w a t e r as e s t i m a t e d activated

sludge

according

2076

Analyses

Dissolved

organic

were

filtered

SM),

and analysed

described

carbon

through

in

0.2

~m

cellulose

Adsorbable

organic

of

nitrate

halides

on 2 x 50 ml s u b s a m p l e s

H N O 3 a n d 0.I ml IM a q u e o u s Na2SO3) according

subsamples

each

filters

fifty

ml

(Satorius

for T O C on a D o h r m a n n DC 52 A c a r b o n a n a l y z e r as

(6).

in d u p l i c a t e

Two

(DOC).

(AOX)

were

(preserved with

analysed

0.I ml conc.

on a D o h r m a n DX 20 TOX a n a l y z e r

to the p r o p o s e d A S T M m e t h o d

(7).

These parameters

were

u s e d to f o l l o w the c o u r s e of d e g r a d a t i o n .

Analyses/tests

on

the

non-biodegradable

fraction

(the

residue)

o b t a i n e d from the a e r o b i c s t a b i l i z a t i o n test i n c l u d e d the following:

l)

Short-term

costatum,

(14C-uptake) for

toxicity

based

on

test

with

measurement

the

of

marine

(8). The t e s t d u r a t i o n was

potentially

bioaccumulating

diatom

inhibition

of

6 hours.

organics

Skeletonema

photosynthesis

2) T L C - s c r e e n i n g

performed

on h e x a n e

ex-

t r a c t s of the r e s i d u e on C18 r e v e r s e - p h a s e t h i n l a y e r c h r o m a t o g r a p h y plates

(9).

R e s u l t s and d i s c u s s i o n

The

results

of the

screening

test

on the two w a s t e

in s e a w a t e r at 4°C and 15°C are p r e s e n t e d

OEC~A0&TION 1% OOC )

in Fig.

O---O

water

samples

2.

5~.~L.E A 5AMPLE 8

IS'C

j

r

~

O

Fig.

2.

Time

course

15"C -~

0

of b i o d e g r a d a t i o n

in the

4°C and 15°C as f o l l o w e d by DOC.

screening

test

at

2077

The

studies

chemical

revealed that approximately

10% of DOC in both petro-

waste waters were degraded at 4°C, while 30-40% and 50%,

respectively,

were

non-degradable

degraded

fraction,

at

more

15°C.

For characterization

concentrated

samples

were

of the obtained

from the aerobic stabilization test as illustrated in Fig.

%

3..

DEGRADATION

"lOOm

80"

JI. Somple

A

~

3

Sample

60-

aO"

20

0

Fig.

1

2.

.

3.

.

Biodegradability

3.

/, .

.

5

.

6

7

;

8

w~j~

;o

trend in the aerobic stabilization

test

at 15°C followed by DOC.

As

shown,

days, The

40%

and

70%,

respectively,

were

not

degraded

after

60

at which time the degradation rate was very slow.

screening

test

indicates

A O X is readily degradable. inherently

degradable

or

how

large

a fraction

of the

In the aerobic stabilization non-degradable

fraction

DOC

or

study,

the

is isolated

for

further testing and analyses. The highest percentage of degradation obtained

in

either

tests

is

used

for

the

illustration

given

in

Figure 4 of the overall degradability of the two waste water samples.

2078

ple B

Fig.

4.

E v a l u a t i o n of b i o d e g r a d a b i l i t y of w a s t e w a t e r samples.

T a b l e 1 shows the r e s u l t s of t h e t o x i c i t y t e s t w i t h S k e l e t o n e m a

as

p e r f o r m e d on freshly c o l l e c t e d w a s t e w a t e r s a m p l e s and on the slowly degradable

fractions

( c o r r e c t e d for dilution),

respectively.

TABLE 1 T o x i c i t y of w a s t e w a t e r and r e s i d u e s

from a e r o b i c s t a b i l i z a t i o n

as

m e a s u r e d in a p h o t o s y n t h e s i s i n h i b i t i o n t e s t w i t h S k e l e t o n e ~ a c o s t a tum. R e s u l t s g i v e n as m l / l u n d i l u t e d water.

EC i0 = E f f e c t i v e Con-

c e n t r a t i o n g i v i n g 10% inhibition.

EFFECT LEVELS SAMPLE

Petrochemical wastewater A

Residue

EC 50

EC 90

ml/l

ml/l

0,18

0,8

3,6

0,47

4,3

39

28

182

>500

>500

>500

from Aerobic Stabilization

of w a s t e w a t e r A

Petrochemical wastewater B

Residue

EC I0 ml/l

from aerobic stabilization

of w a s t e w a s t e w a t e r B

Sample A was

35

found to be far m o r e

t o x i c to the d i a t o m t h a n s a m p l e

B. The t o x i c i t i e s of t h e r e s i d u e s a f t e r s t a b i l i z a t i o n w e r e a f a c t o r of 3-5 t i m e s samples.

less

than

the

toxicities

of

the

freshly

collected

2079

The

decreased

toxicity

showed that

some of the c o m p o u n d s

contrib-

u t i n g to the t o x i c i t y of the w a s t e w a t e r s w e r e d e g r a d a b l e .

The

result

of the s c r e e n i n g of the

cumulable compounds

samples

for p o t e n t i a l l y

bioac-

is s h o w n in T a b l e 2. TABLE

2

Log P o w of c o m p o u n d s in the r e s i d u e o b t a i n e d from the TLC-screening.

SAMPLE

Log Pow

Petrochemical

w a s t e w a t e r sample A

6,65 4,95

Residue

f r o m a e r o b i c s t a b i l i z a t i o n of w a s t e w a t e r A

4,65 2,59

Petrochemical wastewater sample B

6,65

Residue

3,05

from aerobic stabilization

of w a s t e w a t e r

B

S a m p l e A and B c o n t a i n e d s u b s t a n c e s w i t h a h i g h p o t e n t i a l accumulation

as j u d g e d f r o m

(log Pow)-

for bio-

T h e s e s u b s t a n c e s w e r e shown

to be d e g r a d a b l e or to be t r a n s f o r m e d into less l i p o p h i l i c compounds in

the

aerobic

nondegradable (log P o w

=

stabilization compounds

4.65)

were

test.

with

a high

still

present

On

the

other

potential in the

of

hand,

slowly

or

bioaccumulation

residue

of

sample

A,

w h i l e the c o m p o u n d s in the r e s i d u e of sample B w e r e less l i p o p h i l i c (log P o w = 3,05). In

a

hazard

wastes, to be able

evaluation

characterization

sufficient fraction

non-toxic

and

ting compounds

In t h i s

of

the

a

effects

of

organic

of the b i o d e g r a d a b i l i t y m a y be c o n s i d e r e d

in m a n y cases

and

environmental

slowly

or

at the same t i m e

if the w a s t e c o n s i s t s non-degradable

of a d e g r a d -

fraction

free from p o t e n t i a l l y

which

is

bioaccumula-

in s i g n i f i c a n t amounts.

situation,

the m e t h o d s d e s c r i b e d are c o s t - e f f e c t i v e

and at

the s a m e t i m e i n d e p e n d e n t of the a v a i l a b i l i t y of a s p e c i f i c chemical

2080

analysis for the compounds in the waste - provided, of course, that methods

exist

for

visualization

c o m p o u n d s on TLC plates. general

classes

of

of

potentially

bioaccumulative

(This can be judged from k n o w l e d g e of the

compounds

likely

to

be

present

in

the

waste

water.)

If, as in the case of w a s t e w a t e r sample A, slowly or n o n d e g r a d a b l e fractions

were

compounds,

a more t h o r o u g h chemical analysis would be advisable.~

The

results

toxic

and

of GC/MS

contained

potentially

bioaccumulating

screening of the wastewater samples A and B

have b e e n reported elsewhere

(10).

CONCLUSION

In o r d e r to

illustrate a method for investigating the b i o d e g r a d a -

bility of complex wastes, a study of the d e g r a d a b i l i t y of two petrochemical w a s t e w a t e r s has been reported. The m e t h o d is based upon n o n - s p e c i f i c s~,mmary parameters to follow the course of d e g r a d a t i o n in c o m b i n a t i o n with

a characterization by toxicity tests

and TLC

s c r e e n i n g for b i o a c c u m u l a t i v e substances.

In m i x t u r e

A,

45%

of the

ready b i o d e g r a d a b i l i t y of c a r b o n of

DOC

study

m i g h t be

was

residual

40%

significant

within

with

of toxic

degraded

in screening test

considered as readily degradable.

degraded

performed

DOC was

(shake flask die away test). This

DOC

60 days

a higher was

effect

in a so-called

concentration

sldWly

or

Another

15%

stabilization

of waste

non-degradable,

for

fraction

water.

and

The

showed

on hhe photosynthetic activity of

a

algae

at a c o n c e n t r a t i o n of 0.47 ml/l. In addition, the residue contained p o t e n t i a l l y a c c u m u l a t i n g compounds with log Pow = 4.65.

In sample B, waste w a t e r from another petrochemical industry, 20-30%

only

of the DOC was degraded in the shake flask screening test,

and a n o t h e r 10-20% in 60 days in the stabilization test. The residual 60% DOC was slowly or non-degradable, and showed a s i g n i f i c a n t toxic

effect on the p h o t o s y n t h e t i c activity of algae at a concen-

tration of 35 ml/l. The residue contained p o t e n t i a l l y accumulating compounds w i t h log Pow = 3.05. In a hazard evaluation special emphasis must be put on the slowly or non-degradable compounds, the

propensity

chronic

toxic

to

cause

effects.

long term

effects

bioaccumulation

Evaluating only the biodegradability,

m i g h t expect sample B to be most hazardous, degraded.

as

having or one

as only 30% of DOC was

The t o x i c i t y tests with algae and the TLC s c r e e n i n g for

2081

potentially

accumulating

compounds

show,

on the

other

hand,

that

sample A should be considered more hazardous. In

conclusion,

the

non-compound

specific

analyses

in c o m b i n a t i o n

with toxicity tests and TLC-screening can be used to screen a mixture of chemicals pounds.

for environmentally

If such compounds are found,

harmful n o n - d e g r a d a b l e

com-

it is recommended that speci-

fic analyses be p e r f o r m e d to identify these compounds. Acknowledgement The b i o d e g r a d a b i l i t y

studies,

toxicity tests,

and TLC screenings,

for p o t e n t i a l l y bioaccumulating compounds were skilfully p e r f o r m e d by the technicians Ulla

Lund

Connie Seir~ and Lis S~ndergaard.

participated

in the planning

Ole Kusk and

of the toxicity

tests

and

TLC-screenings. Dr. Lars Renberg, the National Swedish Environment Protection Board, Special Analytical Laboratory, Stockholm, Dr. Ake Granmo, Kristineberg

Marine

valuable study

Laboratory,

Kristineberg,

ideas and discussions

has

been

MUST-project, coordinator,

performed

as

Sweden,

contributed

in the planning of this study. a

contract

study

and the author is thankful to Mr. G6teborg

with

for

the

The

Swedish

Knut Andren,

MUST

for permission to publish the results.

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P.

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[Received in Germany 14 November

1988)

V.

Insti-